Mixture control



Dec., 14, 1937.

G. E. BEARDSLEY, JR., ET AL MIXTURE CONTROL Filed May 25, 1954 Patented Dec. 14, 1937 UNITED s'rAv'rEs MIXTURE CONTROL Guy E. Beardsley, Jr., Hartford, and Wright A. Perkins, West Hartford, Conn., assignors, by mesne assignments, to United Aircraft Corporation, a corporation of Delaware Application May 25, 1,934, Serial No. 727,508

21 Claims.

This invention relates to mixture control mechanism and more particularly to mechanismior controlling the jets in carburetors in response to changes in atmospheric pressure.

In the operation of airplanes, powered byinternal combustion engines it is necessary to adjust the air-fuel ratio in accordance with diff tity of fuel.

One of the objects of this invention is to provide means for controlling the fuel-air ratio of acombustible mixture. f

Another object is to provide automatic means for controlling the jets of a carburetor.

Other objects and advantages will be apparent from the specification and the accompanying drawing which show what is now considered the preferred embodiment.

Fig. 1 is a somewhat diagrammatic view showing a carburetor partly in section, and show--l ing the jet control mechanism.

Fig. 2 is a view similar to Fig. 1, showing another form of jet control mechanism.

' Fig. 3 is a somewhat diagrammatic view showing the connection between the control jets and the main jet.

This invention has been shown in Figs. 1 and 3 as embodied in a carburetor having a body Ill `and a discharge jet l2 located in the throat of a Venturi tube in an intake passage, not Shown. The discharge` jet is fed from a manifold it which, in turn, is fed from a plurality of control jets lt, IB, 20 and 2li. Fuel is led into the chambers above these jets by any suitable means such as conduits 26 and 2B, from the iioat chamber 30 or any other suitable source Nof fuel.

In the modification shown in Fig. 1, jet 2t always open andl 'determines the minimum amount of fuel which can be fed to the main jet under full or wide open throttle conditions. The remaining jets i6, IB, and 20 may be closed by means of needle valves 32, 34, and yBti respectively. These valves are normally held off their Each valve sage of fluid thereby and to act as a piston to force the valve to closed position.

The uid for closing the needle valves is controlled by a piston valve 42 adapted to slide in a cylinder Mi, and connect 4ports 46, 42, and 55 with either a source of fluid pressure or witha drain. Fluid pressure may be introduced through pipe' 52 and pipes 58 and 55 may be connected with a drain. This then provides a. balanced valve'for operating the needle valves so that only the frictional forces must be overcome in the operation of the Valve.

This piston valve ft2 may be operated either by manual means or by a pressure responsive device such as the bellows 82 and its cooperating mechanism, detailed operation of which is described below. By the use of the bellows 32, the operation of the jets becomes automatic and depends only upon the pressure acting upon the bellows 82 and therefore acts to close the jets as the' airplane climbs to higher altitudes and reduced pressures. Any suitable source of m'oi pressure for actuating the jets may he used, such as the pressure oiling system of an internal cornbustion engine.

In. the modication'shown in Fig. 2, a diermt form of jetvcontrol is disclosed. In this modification, fuel is fed to the manifold id through the jets 59, Bil, E52, Si, and 66', all of these iets being fed from a reservoir 68 which, in turn, is fed from the floatchamber and by the conduit 28.

Jet 66 always remains open similar tov the jet.

2t of the modification shown in Fig; I. The remaining jets may be closed by means of a piston lll sliding in the chamber 68. This piston may be manually operated or,.as shown, automatically operated Aby means oi a pressure responsive bellows 82.

'The jet control piston could be operated directly by bellows 82, but the form shown in Figs. 1 and 2 is preferred. The form or' automatic operating mechanism shown in Fig. 2 is substantially the same as that shown in Fig. i. This mechanism will, therefore, be described only in connection with Fig. 2; its application to the structure of Fig. 1 will, it is believed, be apparent from this description and the showing of this iigure. Referring to Fig. 2 the piston m is cocnnected by means of a bar 1I with a huid pressure actuated piston 12 mounted in a cylinder 14. The introduction of fluid into is controlled by valves-'I6 and la connected to a common actuating arm 80. Pressure is introduced into the valve chamber through a pipe l2' andthe, other-portions'of the 'valve chamber are connected'to a drain by means of the pipes 84 as will be evident from the drawing. Operation ofthe valves .toward the right, as seen in.

Fig. 2, will introduce pressure into the right hand end of cylinder 'Il and connect the left hand end thereof with the drain, thus movingl to collapse the bellows I2 and to move the lever arm toward the right as seen in Fig. 2. 'hie bellows l2 may be a sealed bellows filled with a suitable gas, such as air at sea level pressure' under normal temperature, or 'it' may lbe an evacuated bellows having a spring therein to prevent it from collapsing. By the inclusion of air or other gas in the bellows, it is made temperature responsive as well as pressure responslve. This bellows may beplace'd so as to be affected by atmospheric pressure, `or it may be Placed in the intake below the carburetor so asI to be. aiectedo ture in that in by the pressure and temperae. 'I'he term "atmospheric Pressure as used in the following claims is intended to denne pressure acting 'on the bellows under any of these conditions.

. In the operation of this device, a reduction in 'the pressure surrounding the bellows l2 or, an in; the, temperature'I affecting the bel'` lows I2 will vcause the bellows to expand and move the lever I4 toward-'the left, as seen in .Fim 2. This willcause the valves Ilyand 1l to put oil under pressurein the left hand end of chamber. M and move the piston 'l2 towards the right. This, in turn, will compress spring ists sible to obtain a fuel air ratio that win havev and thereby partially collapse bellows 82 which, in turn, will bring. the lever arm 84 and valves 16 and Il back to neutral position andthereby hold piston l2 in vits changed position so that the bellows 82 will not be required to make more .than Blight movements to actuate the piston 12 its full stroke. Movement Aof the piston 12 toward the right in response to a reduction in pressure in the bellows I2 will, of course, cause a movement of the piston 'Il toward the right and act to close oifone or more of the jets 5l, to, t2, and I4. VvBy the correct proportioning of the :lets and the jet operating mechanism, it is posbut a slight variation'for the complete temperature and pressure range of the regulating device. o

This will then provide a means which will-recuire no attention fromjthe operator, and vwill maintain the combustible mixture substantially uniform from the ground up to an altitude cor'- responding to the pressure limits of the device and Vthrough temperature ranges withiny the limits of the device.

, aitnougn this control mechanism' nos beim shown in conjunction with specific mechanism,

it is to be understood that the invention is not limited thereto. and thatthe invention can Alie otherwise embodied and that'the drawing is Ynot.`

to be construed as defining orlimiting the scope of the invention, but as illustrative only. 'nils invention 'maygtherefore be used in other ways and various changes may be made withaioasoi out departing from the spirit and of the invention as delined bythe following claims.

What we claim is: l. In a carburetor having a fuel nozzle, means for'controlling the flow vof fluid through said nozzle comprising a plurality of normally open jets in the fuel line leading to said nozzle, means for selectively closing said jets comprising, a source of iluid pressure, plungers associated with the jets and adapted in one position to close them, and a valve for selectively connecting said plungers -with said source of pressure to move said plungers to close said Jets.

2,. Means for controlling the quantity of fuel fed to a fuel mixing device, comprising a plurality ofv normally open Jets in the fuel line leading to the fuel mixing device, plungers asse-l ciated with .said jets and adapted in one position to close them, resilient means for`normally holding said plungersfaway from said jets .to maintain the-jets in open position, means for introducing fluid pressure to one side-of said plungers to move them to close'l said jets and a valve actuated in accordance with variations in atmospheric pressure for selectively controlling the introduction of uid to saidplungers.

3. Means for controlling the quantity of fuel fedv to a fuel mixing device comprising a conduit through which the fuel is led, lets in' the side f of said conduit, a plunger closing .oneend of said conduit and adapted to slideitherein, said plunger adapted in one position tot cover all but one of said iets and means foi; moving said plunger to uncover the other Jets in accordance with increases in atmospheric pressure.

4. Means' for controlling the quantity of fuel lfed to 'a fuel mixing device comprising in combination a plurality of jets arranged in the fuel line leading to the mixing device, a plunger for controlling said jets, a iluld operated piston operatively connected with for controlling the fluid to perate said-piston, an expansible bellows having a .movable end, a

d plunger, a valvev spring arranged between the v movable end of said bellows'and said piston and adapted to be actuated by movement of said piston and a con- ',nection between the movable end of said bellows device adapted to operate saidV valve vin response to movements of said device, and a connection between said piston and said regulating means. 6. Means for operating a fuel regulating device, comprising, in combination, a pressure and temperature responsive mechanism, a iluid operated piston for moving said regulating device, a valve .controlling the operating fluid for said pistonA for controlling the movements of said piston, a connection between said valve and said-mechanism adapted to operate said valve and'in consequence i said piston in response to pressure and temperaturechanges, a resilient connection between saidl piston and said mechanism adapted upon movement of said piston to restore said mechanism to its original position. y

7. In a carburetor, a jet controlling plunger.

a for riuivins said` plusser to control than jets. a preS'ure and temperature responsive device for controlling the position. of said piston and said plunger and a resilient connection between said piston and said device adapted upon movement of the piston to impose forces on said device to oppose the movement that caused the movement of the piston and to bring the device to its o position.

8. In a carburetor, a' jet controlling plunger, a piston connected therewith for moving said plunger to control the jets, a pressure and tein-v peraimre responsive device for controlling the position of said piston in accordance with pressure and temperature conditions, a resilient conneetion between said piston and said device, said piston adapted to compress or expand said resilient connection in opposition to movements of said device.

9. In a. carburetor, a jet controlling plunger, a uid operated piston connected therewith for moving said plunger to control the jets, a valve controlling the operating fluid for said' piston 'foi-'controlling the movements'of said piston, a

premi-e and temperature responsive device for controlling the position of said valve, said valve haring a neutral position and having operative tions on either side of the neutral position, a resilient connection between said piston and said device, said piston adapted to compress or expand said resilient connection to bring the device and valve hackv to neutral position after each movement to an operative position.

nection between said piston and said device ill',

adapted to exert a variable force on said device in' accordance with the position of said piston, said piston adapted to vary the force exerted by the resilient means to oppose the movement of the device which caused the movement of said piston.

il. In a carburetor, in combination, a fuel nozzle and means for regulating the ow of fuel to said nozzle in accordance with variations in atmospheric pressure, said regulating means comprising a pressure responsive device having a movable portion, a iiuid pressure operated piston, means for controlling the operation of said piston connected to the movable portion-of said pressure responsive device for movement therewith, whereby movement of said movable portion `causes movement of said piston, a spring connecting said device and said piston whereby movement of said device to compress said spring causes movement of said piston to further compress said spring and return said movable portion to its original position, means for varying the effective size of the conduit leading to said nozzle to vary the dow of fuel thereto and a connection between said piston and said last mentioned means whereby movement-cf said piston will move said last mentioned means to vary the flow of fuel to said nozzle.

l2. In a carburetor having a fuel nozzle fed by a plurality of fuel jets, means for controlling the quantity of fuel fed to said nozzle by said jets comprising a plurality of independent, huid pressure operated, jet controlling plunger-s.

13. In a carburetor' having a plurality of fuel jets, means for controlling the quantity of fuel fed by said jets comprising a plurality of independent, uid pressure operated, jet controlling plungers and means controlled by atmospheric pressure for selectively operating said plungers at predetermined atmospheric pressures.

14. In a carburetor having a fuel nozzle, means for controlling the flow of fluid through said nozzle comprising a plurality of normally open jets in the fuel line leading to'said nozzle, fluid pressure operated means for individually closing said jets and a valve for selectively connecting said last 'named means with a source of fluid pressure.

15. Means for controlling the quantityof fuel fed to a fuel mixing device comprising a fuel line leading to said fuel mixing device, a plurality of fuel metering jets arranged in said fuel line,

means for closing said jets and iluid pressure a operated means for selectively operating said closing means and means responsive to atmospheric pressure for controlling said fluid pressure operated means, to vary the quantity of fuel delivered per unit volume of air.

16. In a carburetor, means fuel air ratio of the carburetted mixture, comprising a plurality of fixed fuel4 jets and means for selectively controlling said jets, a piston for moving said controlling means, a pressure responsive device'for controlling the position 'of said piston and said controlling means andaresilient connection betweengsald piston and said device adapted upon movement cf the piston to impose forces on said device to oppose the movement that caused the movement of the piston and to bring the device to its original position.

17. In a carburetor, jet controlling means, a piston for moving said means to control the jets, an expanslble chamber device for controlling the position of said piston and said means, means for moving" said piston upon movement of said expansible chamber device, and a resilient connecfor regulating they tion between the piston and said device adapted vice to its original position.

18. In a carburetor having a fuel nozzle, means for controlling the iow of iiuid through said noz-A zle, comprising a plurality of jets ln the fuel line leading to said nozzle, said jets adapted to be selectively opened and closed, a. piston valve assoclated with said jets 'and adapted to control the opening and closing of said jets and means responsive to atmospheric vpressure for moving said piston valve to control said opening and closing.

19. In a carburetor ofthe float chamber type, a fuel nozzle, means for regulating the quantity of fuel delivered by said nozzle per unit volume of .air passing said nozzle to thereby regulate the fuel-air ratio of the carbureted mixture, said regulating means comprisingja plurality of fuel metering jets in the fuel line leading to said nozzle, a piston valve for controlling the opening and closing of said jets, and means responsive to atmospheric pressure for controlling said piston valve to selectively close said jets upon decreases in atmospheric pressure.

20. In a carburetor having a fuel nozzle, means for controlling the ow of fuel through said noz- Cil jetsand means tot selectively opening or closing' said jets, said last named means comprising s.

piston valve associated with said Jets and means responsive to atmospheric pressure for moving said piston valve to control said opening and clos- GUYE. BEARDsIm, Jn. i wnmn'r n. mams. 

